Mold in Your Home

The Department of Public Health follows the State Sanitary Code for Housing, which applies to rentals only. The Health Department does not test for mold but will address concerns that may cause mold (i.e. leaks, flooding, chronic moisture, etc.) in rentals. The Health Department cannot require an owner to test for mold.

  • Housing occupants can test for mold at their own expense, but the Health Department cannot issue a correction order based on the test results (since there are no mold standards)
  • The Health Department cannot order the owner to reimburse the occupant for testing expenses, damaged personal belongings, or cleaning of personal belongings
  • Occupants can pursue their own legal action against an owner per 105 CMR 410.010(c)

Molds are fungi that are part of the natural environment. Outdoors they break down dead organic matter. Indoors, however, they should be avoided. The key to avoiding indoor mold is to understand how molds grow and how to minimize the conditions that allow this growth.

Mold SporesMold spores in the corner of a room.

Molds reproduce by making microscopic spores that can be released into the air. Spores float through outdoor and indoor air and can survive in harsh environments. Given the right conditions, spores will grow into mold relatively quickly, often in just 24 to 48 hours.

What Spores Need to Grow Into Mold

For spores to grow into mold, they need three things:

  1. Food
    • Outdoor vegetation and building materials
    • Indoor materials, especially porous ones, such as paper, cardboard, ceiling tiles, wood, paint, carpet, and fabric
  2. Moisture
    • Water leaks or flooding
    • Water vapor, the result of high relative humidity
  3. Optimum Temperatures
    • 40°-100°F (70°- 90°F ideal)
    • Mold can still survive in non-optimum temperatures

Of these three, controlling moisture is the condition we can have the most effect on, so we should start our mold control efforts there.

Common Molds

There are a number of common indoor molds. These include Alternaria, Aspergillus, Cladosporium, and Penicillium. Have you heard the term "toxic mold"? According to the Centers for Disease Control and Prevention (CDC), the term "toxic mold" is not accurate. While certain molds are toxigenic, meaning they can produce toxins (specifically mycotoxins), the molds themselves are not toxic/poisonous. Hazards presented by molds that may produce mycotoxins should be considered the same as other common molds which can grow in your house

There is always a little mold everywhere - in the air and on many surfaces. There are very few reports that toxigenic molds found inside homes can cause unique or rare health conditions such as pulmonary hemorrhage or memory loss. These case reports are rare, and a causal link between the presence of the toxigenic mold and these conditions has not been proven.

The Institute of Medicine has linked indoor mold exposure to three health impacts:

  • Upper respiratory tract symptoms, cough, and wheezing (in otherwise healthy people)
  • Exacerbated asthma symptoms (in people with asthma)
  • Hypersensitivity pneumonitis (in susceptible individuals)

Certain people (i.e., those with mold sensitivity or laborers) may be more at risk than others. People with mold sensitivity may experience symptoms like:

  • Nasal stuffiness
  • Eye irritation
  • Wheezing
  • Skin irritation

Also, some people (i.e., laborers who have been exposed to large amounts of mold, people who are immunocompromised, or those with chronic lung disease) may also have a more severe reaction to mold and may experience symptoms like:

  • Fever
  • Shortness of breath
  • Fungal lung infections

Non-Health Impacts

As mold grows and spreads, it can cause costly damage to surfaces and structures. In rare instances, occupants may have to vacate their premises because of mold. Remember, the presence of mold usually indicates that there is a moisture and dampness problem. Moisture and dampness can compromise building structures and contribute to pest infestations.

Testing for Mold

While it is possible to test mold and identify its type, it is not necessary. The EPA and CDC recommendations for mold remediation are the same for any type of mold. Identifying the type of mold does not change the recommendations. Testing for mold can also be expensive and, even if it is done, there are no accepted regulatory standards for determining tolerable quantities of mold. Rather than spend money on mold testing, the recommendation is to spend it on controlling moisture and removing mold.

Resources for Homeowners and Occupants